The present invention relates to a liquid distributor for distillation column. It applies in particular to the air distillation columns on board floating structures such as floating oil platforms or barges.
The pressures referred to below are absolute pressures.
Floating oil platforms produce residual gases. For economic and environmental reasons, it is becoming more and more necessary to recover these gases. One method consists in converting them into heavier hydro-carbons, which are in liquid form and are therefore easier to transport, using the Fischer-Tropsch process which consumes large amounts of oxygen.
It would therefore be beneficial to be able to install an air distillation column on board a floating platform or a barge, but proper operation of equipment of this type is compromised by serious difficulties. Specifically, a first imperative is for the liquid to be distributed uniformly at the column head over the entire cross-section of the latter, despite the oscillations of its axis due to the motion of the waves.
The object of the invention is to provide a liquid distributor whose operation has very little sensitivity to oscillations of this type.
To that end, the invention relates to a liquid distributor for distillation columns, characterized in that it comprises:
a primary distributor which delimits a closed volume provided with liquid predistribution openings which open into the column;
means for feeding the primary distributor with liquid under a pressure substantially greater than the internal pressure of the column; and
a secondary distributor which occupies substantially the entire cross-section of the column, which includes a gas overhead in communication with the internal space of the column and which is subdivided by partitions into a plurality of compartments, each of which receives liquid originating from at least one of the said openings of the primary distributor, this secondary distributor having a bottom provided with orifices for fine distribution of the liquid over virtually the entire cross-section of the column, the number of these orifices being very much greater than the number of openings of the primary distributor.
The distributor according to the invention may have one or more of the following characteristics:
each compartment receives liquid from a single opening of the primary distributor;
all the compartments have substantially the same area and the same perforation factor;
the primary distributor comprises an array of perforated tubes;
the array of perforated tubes comprises a series of parallel perforated tubes, each of which is plumb with a straight funnel of the secondary distributor;
the said feed means comprise a phase separator and a compression and feed conduit connected upstream to the lower part of this separator;
the feed means pass through a supercooler.
The invention also relates to a distillation column comprising a distributor as defined above.
In one embodiment of such a distillation column, the said liquid distributor is arranged at a first level of the column, in particular at the column head, and the column includes, at at least one second level, liquid collection means on top of a second liquid distributor as defined above whose primary distributor is connected to second means for compressing the liquid collected.